improve information about using the apt cookbook
improve information about using the apt cookbook

DataDog/opscode-cookbooks,dagolden/opscode-cookbooks,pcreux/cookbooks,beni55/cookbooks,dbroeglin/cookbooks,dbroeglin/cookbooks,gravitystorm/cookbooks,gravitystorm/cookbooks,DataDog/opscode-cookbooks,pgroudas/cookbooks,pcreux/cookbooks,pgroudas/cookbooks,dagolden/opscode-cookbooks,dbroeglin/cookbooks,beni55/cookbooks,DataDog/opscode-cookbooks,beni55/cookbooks,beni55/cookbooks,pcreux/cookbooks,beni55/cookbooks,gravitystorm/cookbooks,pgroudas/cookbooks,dagolden/opscode-cookbooks,beni55/cookbooks